Hi Dear,
Welcome to HCM.
UNDERSTANDING YOUR CONCERN.
Thanks for your query .The dark spot on your lower lip can occur because of many reason like over exposure to sun ,
allergic reaction to any product you use on face or oral cavity like tooth paste ,
hormonal changes and
vitamin deficiency. It is rare that this is the symptom of cancer.
Sometimes frequent licking of lip remove natural moisture of lip and make it dry(chapped lip) ,dryness can also caused black spot on lip.
I would suggest you to apply lip balm to your lip having SPF 15 to protect from sun exposure, drink at least 7-8 glasses of water per day .apply lemon juice mixed with honey on lip for 10 minutes 2 times daily. Avoid smoking,drinking alcohol and licking and picking of lip.
If symptoms persists for more then a week then
consult dermatologist for perfect examination to rule out other conditions like melanocytic naevus and cancerous lesion.Doctor may order biopsy.Doctor may prescribe
hydroquinone cream for hyper pigmentation.
Hope your concern has been resolved.
Get well Soon.
Best Wishes,
Dr. Harry Maheshwari